Permselective membranes suitable for use in desalination of aqueous solutions are the subject of numerous patents. Richter et al. U.S. Pat. No. 3,567,632 discloses membranes made of organic, nitrogen linked aromatic polymers. Cadotte U.S. Pat. No. 4,277,344 discloses permselective multi-layer membranes in which there is a microporous polysulfone substrate layer and a superposed polyamide layer made from an aromatic triacid halide and an aromatic diamine. Scala et al. U.S. Pat. No. 3,744,642 discloses multilayer membranes in which one layer is porous substrate and the juxtaposed layer is a polyamide, a polyphenylester, or a polysulfonamide. Weyland et al. U.S. Pat. No. 3,649,687 discloses the use of 1,3,5-cyclohexane tricarbonyl chloride in the production of crosslinking agent: 1,3,5-cyclohexane triisocyanate. Hara et al. U.S. Pat. No. 4,353,802 discloses semipermeable composite membranes in which the membrane material is crosslinked using polyfunctional aromatic acid halides. More recently U.S. Pat. Nos. 4,520,044 and 4,529,646 disclose permselective multi-layer membranes in which there is a microporous polysulfone support and a polyamide layer made from 1,3,5-cyclohexane tricarbonyl chloride.